Vibrating surface for sound-transmission



(No Model.)

v T. A. WATSON.

Vibrating Surface for Sound Transmission.

No. 232,862. Patented Oct. 5,1880.

W't 55555. I fi/a inr.

away. m mm UNITED STATES PATENT Grrrca THOMAS A. WATSON, OF EVERETT, MASSACHUSETTS.

VIBRATING SURFACE FOR SOUND-TRANSMISSION.

SPECIFICATION forming part of Letters Patent No. 232,862, dated October 5, 1880.

Application filed April 12, 1880. N0 model.)

To all whom it may concern Be it known that I, THOMAS A. \VATSON, of Everett, county of Middlesex, State of Massachusetts, have invented an Improvement in Vibrating Surfaces for Sound-Transmission, of which the following description, in connection with the accompanying drawing, is a specification.

My invention relates to telephones, and has for its object to increase the amplitude of the vibrations of the armature of the transmittingtelephone or of any instrument used for transmission, as a carbon transmitter. To accomplish this result I make use of fluid or gaseous pressure, confining the fluid or gas in a chamber or reservoir of rigid material, having a part of its surface of a considerable area removed and the opening closed by aflexible diaphragm suitable to be vibrated by the usual sound-vibrations, and having also a much smaller opening, which may be fitted with a piston or closed by another elastic or flexible diaphragm. The piston or smaller diaphragm may be or sustain the armature of a magnet, or they may act upon the carbon of a microphone-transmitter, or act in any other usual way to cause electric pulsations; and it will be understood that the amplitude of the vibrations of the smallsurface will be as many times greater than those of the large surface as its area is less, and theelectric eflect to cause transmission of sound will be proportionallyincreased or multiplied.

The drawing shows, in longitudinal section, sufficient portion of a telephone to illustrate my invention.

The reservoir 0, of material sufficiently rigid not to yield under the pressure of the contained fluid or gas, is shown as funnel-shaped and screw-threaded on its outside at the large open end, where a diaphragm, b, which may be of the kind generally employed, may be secured by screwing on a mouth-piece, 0, of usual construction. The edge of the reservoir is made smooth and the diaphragm carefully fitted thereto and provided with packing, or with a coating of lead or other suitable material, if necessary, in order to make a perfectly tight joint.

The smaller opening is shown as provided with a tight-fittin g piston, d, which may carry at its outer end a piece of soft iron, as the armature of the magnet e, or may be arranged to press against a carbon point, to cause by its vibration fluctuations in an electric current induced by the magnet or passing through the said carbon.

The plunger cl is shown as connected with a diaphragm, d, which in thiscase merely acts as a spring to give resilience to the movement of the piston (1.

Any kind of liquid or gaseous fluid may be used in the chamber Ct, but I find in practice that air, water, alcohol, and glycerine each give excellent results, and it is sometimes desirable to use a flexible diaphragm as the smaller vibratory surface instead of the piston b.

It is obvious that this invention may be applied to any apparatus in which the sound-vibrations of the air are to set a plate or dia phragm in vibration-as, for example, in a phonograph-and that the plane of the smaller surface may be placed at any desired angle to that of the larger surface.

It may sometimes be desirable to use this apparatus in connection with a receiving or speaking instrument, the larger plate then being set in vibration by magnetic action or mechanically, and the smaller one giving out sound. If it should be desired, more than one small surface may be set in vibration from the vibrations of a larger surface through the medium of fluid-pressure.

I claim- 1. That improvement in the art or method of transmitting or reproducing sound-vibrations which consists in increasing the ampli tude of said vibrations by means of the pressure of a confined fluid, substantially as described.

2. In an apparatus for transmitting soundvibrations, a chamber or reservoir to contain a fluid, provided with two flexible or movable surfaces of different area, whereby the vibratory movement of the larger surface imparts, through the medium of the fluid, a similar vibratory movement to the smaller surface, all the movements of the smaller surface being proportional to those of the larger surface, but of increased amplitude, thereby giving more powerful effects, substantially as described.

3. In a telephonic apparatus, a fluid-chainher having alarge opening, and a telephone In testimony whereof I have signed my diaphragm andmouth-piecetightlyfitted therename to this specification in the presence of IO on, and. a smaller opening and a movable surtwo subscribing Witnesses.

face to close the same whereby vibrations of the larger diaphragm transmit, through the THOMAS WATSON fluid in the chamber, similar vibrations, but Witnesses:

of greater amplitude, to the smaller surface, J 0s. P. LIVERMORE,

substantially as described. N. E. G. WHITNEY. 

